r15suk

OK i know that drilling holes in the airbox is done for sound and not performace (i have race cans on my motorbikes purely for sound :-) ), but are there any downsides to doing this.

Also where do i drill them and what size?

Cheers
Simon

jamest

The only downside I can think of is that you are likely to fail noise tests at trackdays, for this reason I took the cone filter off that a previous owner fitted to my car. Also, if you change your mind and want to go back to an undrilled cover, buying a new box is expensive!

Goughary

I'm sure that if you ask around - someone with holes that doesnt want the holes will trade with you...

I wish you were in the states - I'd trade for my holed box cover. I'd love to see what the difference is. Mine was drilled when I got it.

911Jetta

^^^^^
That's the biggest negative....you or the next buyer might perfer a stock air box cover.

Appearance aside, there are few negatives about the noise.

Mine has been drilled for a couple of years so I can't compare to stock anymore, but the level is subdued (but slightly louder) at part throttle. A holed air box cover is definitely a lot louder at full throttle or above 4,000 RPM. Sounds like a roar!

RobertF

My car is completely stock and I've never heard the drilled air cover before. Is the increased sound only in the cabin or does it also change the sound at the tail pipe. Thanks.

LouZ

There is a pattern of squares on the cover, drill the holes in each of the "complete" squares to the diameter within the square.

Steve Weiner-Rennsport Systems

Hi Simon,

While I'm unable to address this modification on other vehicles, I can tell you that adding 5-6, 2" holes to the airbox cover is worth 2-3 BHP.

While not noticeable, its certainly measurable in back-to-back dyno testing so IMHO, its worthwhile doing in the pursuit of more performance.

Sounds nice, too.

jimq

Take the front cover off and duct tape the air filter on and drive it and see if you like it. Make sure the seal is good on the edges to keep sand from getting in.

bw-porsche

One answer to your query would be to look out for a drilled airbox on ebay as I did. So now I have both drilled and stock airboxes. I can recommend using the drilled one for a better, deeper roar! Good luck. Brian.

r15suk

When i got the car, i got another undrilled airbox with it so i'm sorted on that front :-)

Great, good news all round :-) :-)

Cheers
Simon

911URGE

+1

I recommend having both. The second complete airbox cost me me maybe $75US. The only downside is I tend to "gas" it a little more to hear the nicer engine sound.

jody stowitts

RobertF: Beware of tempation. What the hell is another 2-3 Hp. unless you're a racer?

Babalouie

Here's what I did on mine...

BGLeduc

Likewise. I liked that look better than the Swiss cheese look of the holes. Call it a poor man's Cup air box cover.

And I will echo what others have said...it sounds fantastic when you dip your right toe into the happy zone.

Brian

martin964

Hello Simon,

I have a drillled airbox I would like to change for a non drilled one! I am in oxford too so just up the road ;-) can you hang fire and maybe we could meet up to see if a swop would save both of us some time and effort??

regards

Martin

p.s. have pm'd you my contact number so drop me a txt if a possible swop is of interest.